SRV Record Lookup

An SRV (Service) Lookup Tool helps you query and retrieve SRV records for a specific domain. SRV records are a type of DNS record used to define the location (hostname and port) of servers for specified services, such as SIP (Session Initiation Protocol) or XMPP (Extensible Messaging and Presence Protocol). This tool is essential for understanding how services are distributed across multiple servers and troubleshooting service routing issues.

What Is an SRV Record?

An SRV record specifies the location of a specific service within a domain, including the protocol and port number. SRV records are widely used in protocols like VoIP and messaging systems, allowing clients to discover the correct server and port number for a given service.

Key Components of an SRV Record

The SRV record consists of several important fields that help direct service traffic to the appropriate server. These include:

• Domain: Specifies the domain for which the SRV record is defined, such as example.com.
• TTL (Time-to-Live): Indicates the length of time the record can be cached by DNS resolvers. Example: 60 seconds.
• Class: Typically set to IN, which stands for Internet.
• Type: Specifies the SRV record type.
• Priority: A numeric value that defines the priority of the service. Lower values indicate higher priority. Servers with lower priority numbers will be used first.
• Weight: A numeric value used to distribute traffic between multiple servers with the same priority. Higher weights receive more traffic.
• Port: The port number on which the service is running (e.g., 5060 for SIP).
• Target: The hostname of the server that is providing the service. For example: sip.example.com.

How to Perform an SRV Lookup?

To perform an SRV lookup, you can use the dig command, which will query the DNS records for a specified domain. Here is an example:

This command queries the SRV record for the SIP service over TCP for the domain example.com.

Using an Alternative DNS Server

Sometimes, you may want to query a specific DNS server instead of your default resolver. For example, to query Google's public DNS server:

This command queries Google's DNS server (8.8.8.8) for the SRV record of the _sip._tcp service for the example.com domain.

Common Issues with SRV Records

• Missing SRV Records: If SRV records are missing, services may fail to function correctly or direct traffic to the wrong server.
• Incorrect Priority or Weight: Misconfigured priority or weight values can cause service requests to fail or be directed to the wrong server, leading to service downtime.
• Invalid Port or Target: Incorrect port or target values in the SRV record can prevent clients from establishing a connection to the service.

How Our Tool Helps

Our SRV Lookup Tool simplifies this process by querying the DNS for SRV records of a given domain. It displays all relevant information, including priority, weight, port, and target servers, making it easier to troubleshoot and configure services in your domain.